#include<bits/stdc++.h>
using namespace std;
int n, m, k, ct;
bool br[35][35];
int st, fin;
bool viss[35];
vector <int> spec[12];
int vis[500], timer = 0, level[500], ptr[500];
queue <int> q;
struct dat { int from, to, capa, flow; };
vector <dat> E;
vector <int> a[500];
void addedge(int u, int v, int wei)
{
    E.push_back({u, v, wei, 0});
    E.push_back({v, u, 0, 0});
    int x1 = E.size() - 2, x2 = E.size() - 1;
    a[u].push_back(x1);
    a[v].push_back(x2);
}
void Edge(int mid)
{
    for (int i = 1; i <= m; ++i)
    {
        addedge(0, i, mid);
    }
    for (int i = 1; i <= m; ++i)
    {
        memset(viss, 0, sizeof(viss));
        for (int j = 0; j < spec[i].size(); ++j)
        {
            for (int t = j + 1; t < spec[i].size(); ++t)
            {
                int u = spec[i][j], v = spec[i][t];
                if (!br[u][v]) continue;
                ct++;
                addedge(i,  ct + m + n, 1);
                addedge(ct + m + n, m + u, 1);
                addedge(ct + m + n, m + v, 1);
                viss[u] = viss[v] = true;
            }
        }
        for (int u : spec[i])
        {
            if (viss[u]) continue;
            addedge(i, m + u, 1);
        }
    }
    fin = m + n + ct + 1;
    for (int i = 1; i <= n; ++i)
    {
        addedge(m + i, fin, 1);
    }
}
bool bfs()
{
    level[st] = 0; vis[st] = ++timer; q.push(st);
    for (int i = 0; i <= fin; ++i) ptr[i] = 0;
    while (!q.empty())
    {
        int u = q.front(); q.pop();
        for (int id : a[u])
        {
            int v = E[id].to;
            if (E[id].capa - E[id].flow < 1 || vis[v] == timer) continue;
            level[v] = level[u] + 1;
            vis[v] = timer;
            q.push(v);
        }
    }
    return vis[fin] == timer;
}
int dfs(int u, int pushed)
{
    if (pushed == 0) return 0;
    if (u == fin) return pushed;
    for (int &cid = ptr[u]; cid < (int)a[u].size(); ++cid)
    {
        int id = a[u][cid];
        int v = E[id].to;
        if (level[u] + 1 != level[v] || E[id].capa - E[id].flow < 1) continue;
        int tr = dfs(v, min(pushed, E[id].capa - E[id].flow));
        if (tr == 0) continue;
        E[id].flow += tr;
        E[id ^ 1].flow -= tr;
        return tr;
    }
    return 0;
}
bool Check(int mid)
{
    E.clear();
    ct = 0;
    for (int i = 0; i < 500; ++i)
    {
        level[i] = 0;
        vis[i] = 0;
        if (a[i].empty()) break;
        a[i].clear();
    }
    timer = 0;
    Edge(mid);
    int f = 0;
    while (bfs())
    {
        while (int pushed = dfs(st, 2e9)) { f += pushed; }
    }
    return (f == n);
}
void solve()
{
    int l = (n + m - 1) / m, r = m, ans = -1;
    while (l <= r)
    {
        int mid = (l + r) / 2;
        if (Check(mid))
        {
            r = mid - 1;
            ans = mid;
        }
        else l = mid + 1;
    }
    cout << ans;
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    if (fopen("input.txt", "r"))
        assert(freopen("input.txt", "r", stdin));
    cin >> m >> n;
    for (int i = 1; i <= m; ++i)
    {
        int x; cin >> x;
        while (x--)
        {
            int u; cin >> u;
            spec[i].push_back(u);
        }
    }
    cin >> k;
    for (int i = 1; i <= k; ++i)
    {
        int u, v;
        cin >> u >> v;
        br[u][v] = br[v][u] = 1;
    }
    solve();
}